CA1069457A - Process for drying water-wet methyl chloride - Google Patents
Process for drying water-wet methyl chlorideInfo
- Publication number
- CA1069457A CA1069457A CA260,895A CA260895A CA1069457A CA 1069457 A CA1069457 A CA 1069457A CA 260895 A CA260895 A CA 260895A CA 1069457 A CA1069457 A CA 1069457A
- Authority
- CA
- Canada
- Prior art keywords
- methyl chloride
- water
- chloride
- distillation
- hydrogen chloride
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 229940050176 methyl chloride Drugs 0.000 title claims abstract description 22
- 238000000034 method Methods 0.000 title claims abstract description 10
- 238000001035 drying Methods 0.000 title claims description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims abstract description 13
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims abstract description 13
- 238000004821 distillation Methods 0.000 claims abstract description 10
- 238000010992 reflux Methods 0.000 claims abstract description 7
- 238000009835 boiling Methods 0.000 claims abstract description 4
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 claims description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 7
- 239000002253 acid Substances 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- JWOLLWQJKQOEOL-UHFFFAOYSA-N OOOOOOOOOOOOO Chemical compound OOOOOOOOOOOOO JWOLLWQJKQOEOL-UHFFFAOYSA-N 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000007038 hydrochlorination reaction Methods 0.000 description 1
- ATADHKWKHYVBTJ-UHFFFAOYSA-N hydron;4-[1-hydroxy-2-(methylamino)ethyl]benzene-1,2-diol;chloride Chemical compound Cl.CNCC(O)C1=CC=C(O)C(O)=C1 ATADHKWKHYVBTJ-UHFFFAOYSA-N 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000001577 simple distillation Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Abstract of the Disclosure Methyl chloride containing water is dried to a low water content by distilling the methyl chloride in the presence of 10-40 molar percent hydrogen chloride, based on the total weight of hydrogen chloride, water and methyl chloride. The distillation is carried out at superatmospheric pressure, preferably 100-300 p.s.i.g., a reflux ratio of 1.3-4 and a temperature of from 100°C. to the azeotropic boiling point at the pressure employed. The methyl chloride dried by this process has a water content of less than 0.04 mole percent.
Description
~L~6~S7 The production of methyl chloride (CH3C1) by the reaction of methanol and hydrogen chloride is well known.
However, some difficulty has been encountered in the recovery and purification of the methyl chloride from the reaction mixtura. For example, simple distillation of the reaction . mixture has resulted in loss of produc~ throuyh reversibility of the reaction under the conditions of the distillation.
In addition, the water and methyl chloride ~orm an azeotrope which is dificult to break. To overcome these problems, the art has resorted to sulfuric acid drying of the distilled product, a process which requires large quantities of the sulfuric acid which is either discarded or dried itself and freed of organic impurities prior to reuse.
It would thus be advantageous to have a process 15 for drying which would not favor the reversible reaction : ~ -and which would result in a useable by-product and not .introduce chemicals foreign to the overall system.
The present invention resides in a method for : drying water-wet methyl chloride which consists of dis-- ~0 tilling the water~wet methyl chloride in the presence of from 10 to ~0 molar % hydrogen chloride based on the total weight of hydrogen chloride, water and methyl chloride, .
under superatmospheric pressure and a reflux ratio of :. .from 1.3 to about 4, and a temperature of from 100C to :. .
the azeotrope boiling point under the pressure o~ said distillation, thereby to produce a kottoms from said distillation, of not~more than 36% aqueous hydrochloric acid and an overhead:of methyl chloride and hydrogen ..
chloride containing less than about 400 molar ppm water.
Increasing pressures:permit increasing temperatures 17,217-F -1-s ~
in the bottoms which form azeotropes of lower concentration hydrochloric acid.
The variables which may be adjusted to provide a lower water content of the methyl chloride andjor a higher or lower acid concen~ration are the molar percent hydrogen chloride,- the reflux ratio, the number of trays (theoretical~ r the pressure and/or temperature. These ~ariables can be varied rather broadly within the general principles o distillation.
The process of the present invention is usaful to dry methyl chloride whether the wetness be from a physical contacting or chemLcal reaction resulting in the co-mingling of the methyl chloride with water. For example, methyl chloride produced by the hydrochlorination of methanol is as readily dried as methyl chloride physically mixed with water as a result of a treatment of a material in the presence of water and methyl chloride.
The process is preferably carried out under super-atmospheric pres~ure from about 100 psig to akout 300 psi~.
It is preferable to employ temperatures at which the azeotrope of aqueous hdyrochloric acid boils at such pressures, although lower temperatures are useful if a high acid concentration is desired. It is also preferable to employ from 12-25~
hydrogen chloride for drying the methyl chloride. Reflux - 25 ratios of between about 1.3 and 4.0 are desirable to obtain efficient use of the hydxogen chloride~ Conveniently, the theoretical number of plates in the rectiier or colwmn can vary from about 10 to about 150.
The introduction of h~drogen chloride into the system to obtain the~desired distillation conditions is . ' ~ ' ~' 17,217-F -2-- ,' .
~6~9~5~7 generally made at the still, but it may be present in the feed as a result of employing an excess over stoichiometric proportion in a reaction, for example in which methyl chloride is produced, or present as a by-product of a process.
Example 1 Methanol (2. 903 lbo -mole) was reacted with 3g.7 molar excess above stoichiometric of hydrogen chloride at 166C. The resulting efluent, methyl chloride, water and unreacted hydrogen chloirde, was fed to a 5 1/2 inch I.D~ x 50 ft. distillation column packed with 1/2 inch saddles.
The still was operated at 250 psig pressure and 210C
reboiler temperature with a reflux condenser at 64C. The molar reflux was set at 2.04. The gaseous product was analyzed for water and ound to contain less than 200 ppm water. The still bottoms was 9.95% a~ueous hdyrochloric acid.
Example 2 The following table reports the results obtained by distilling a feed mixture of methyl ~hloride, water and hydrogen chloirde under the indicated conditions in a similar still as described in Example 1, under the pressure conditions set forth in the tableO The amount of hydrogen chloride indicated in the table is based on the hydrogen chloride, methyl ohlorids and watex in the feed to the distillation section. Most runs were made without measuring the reboiler li~uid temperatuer, thus, the temperature was not controlled at the indicated pressure. The temperature o~ the reboiler was below the azeotropic boiling point, thus yielding a higher acid content than would be obtained if the azeotrope boillng point haO been achieved. ~ ;
' ' 17,~17-F -3-. . .
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.
17, 217-F
However, some difficulty has been encountered in the recovery and purification of the methyl chloride from the reaction mixtura. For example, simple distillation of the reaction . mixture has resulted in loss of produc~ throuyh reversibility of the reaction under the conditions of the distillation.
In addition, the water and methyl chloride ~orm an azeotrope which is dificult to break. To overcome these problems, the art has resorted to sulfuric acid drying of the distilled product, a process which requires large quantities of the sulfuric acid which is either discarded or dried itself and freed of organic impurities prior to reuse.
It would thus be advantageous to have a process 15 for drying which would not favor the reversible reaction : ~ -and which would result in a useable by-product and not .introduce chemicals foreign to the overall system.
The present invention resides in a method for : drying water-wet methyl chloride which consists of dis-- ~0 tilling the water~wet methyl chloride in the presence of from 10 to ~0 molar % hydrogen chloride based on the total weight of hydrogen chloride, water and methyl chloride, .
under superatmospheric pressure and a reflux ratio of :. .from 1.3 to about 4, and a temperature of from 100C to :. .
the azeotrope boiling point under the pressure o~ said distillation, thereby to produce a kottoms from said distillation, of not~more than 36% aqueous hydrochloric acid and an overhead:of methyl chloride and hydrogen ..
chloride containing less than about 400 molar ppm water.
Increasing pressures:permit increasing temperatures 17,217-F -1-s ~
in the bottoms which form azeotropes of lower concentration hydrochloric acid.
The variables which may be adjusted to provide a lower water content of the methyl chloride andjor a higher or lower acid concen~ration are the molar percent hydrogen chloride,- the reflux ratio, the number of trays (theoretical~ r the pressure and/or temperature. These ~ariables can be varied rather broadly within the general principles o distillation.
The process of the present invention is usaful to dry methyl chloride whether the wetness be from a physical contacting or chemLcal reaction resulting in the co-mingling of the methyl chloride with water. For example, methyl chloride produced by the hydrochlorination of methanol is as readily dried as methyl chloride physically mixed with water as a result of a treatment of a material in the presence of water and methyl chloride.
The process is preferably carried out under super-atmospheric pres~ure from about 100 psig to akout 300 psi~.
It is preferable to employ temperatures at which the azeotrope of aqueous hdyrochloric acid boils at such pressures, although lower temperatures are useful if a high acid concentration is desired. It is also preferable to employ from 12-25~
hydrogen chloride for drying the methyl chloride. Reflux - 25 ratios of between about 1.3 and 4.0 are desirable to obtain efficient use of the hydxogen chloride~ Conveniently, the theoretical number of plates in the rectiier or colwmn can vary from about 10 to about 150.
The introduction of h~drogen chloride into the system to obtain the~desired distillation conditions is . ' ~ ' ~' 17,217-F -2-- ,' .
~6~9~5~7 generally made at the still, but it may be present in the feed as a result of employing an excess over stoichiometric proportion in a reaction, for example in which methyl chloride is produced, or present as a by-product of a process.
Example 1 Methanol (2. 903 lbo -mole) was reacted with 3g.7 molar excess above stoichiometric of hydrogen chloride at 166C. The resulting efluent, methyl chloride, water and unreacted hydrogen chloirde, was fed to a 5 1/2 inch I.D~ x 50 ft. distillation column packed with 1/2 inch saddles.
The still was operated at 250 psig pressure and 210C
reboiler temperature with a reflux condenser at 64C. The molar reflux was set at 2.04. The gaseous product was analyzed for water and ound to contain less than 200 ppm water. The still bottoms was 9.95% a~ueous hdyrochloric acid.
Example 2 The following table reports the results obtained by distilling a feed mixture of methyl ~hloride, water and hydrogen chloirde under the indicated conditions in a similar still as described in Example 1, under the pressure conditions set forth in the tableO The amount of hydrogen chloride indicated in the table is based on the hydrogen chloride, methyl ohlorids and watex in the feed to the distillation section. Most runs were made without measuring the reboiler li~uid temperatuer, thus, the temperature was not controlled at the indicated pressure. The temperature o~ the reboiler was below the azeotropic boiling point, thus yielding a higher acid content than would be obtained if the azeotrope boillng point haO been achieved. ~ ;
' ' 17,~17-F -3-. . .
- . . ~ , . - :
~:D6~57 O O O O O O , ....
In t~ In Ir) In In IO ~ ~ N ~ Ll) 111 ~ t~l ~_ .
U~
X o ~-~1 ~ cn c~ ~
CO 1~ r~ ~ o o ~ ~ D
~ (d . . . . . . . .
P~ t~ --1 ~1 ~I N N ~ 1--l ~ ~ r~l .--1 ~) ~1 _ . _ ~ , U~ o~o ~ ~ ~ ~ C~l ~ O ~ ~ ~ r~
~ U7 ~ 0 1~ ~1 O ~ .,,...,,.....
~) O ~) ~ ,_1 ,1 ,1 ~1 ~ ,-1 ~ el~ r~) t.D ~ L~) m ~
. . _ ~
..
. . *10 . .
~ ~ r-l N al 1` ~1 ~ N a~ ~`1 ~ . , .
O~ OoOoOOOOOOOOO . ,' f C~l r) . ~
.. , t~ OOOOOOOOOOOOO
L
G`~O ., ~ ~ a~ O O ~1 O O ~ ~ r o o 'I a) ~
~) o ~ ~ ~ u~ Ln X ~i ~ ') ~1 ~ N ~ ~ ~) rf) ~ ~ N t~
o o~o ~ ~ o ~ ~ ~ o o a~ ~ ~ I~ ~ o o ............. .
a) o 0~ 0~ ~ In In C~ C~ ~ ~ ~ ~ Ln In ~ ~ ~ ~ ~ m ~ ~D W ~ r~ ~ :
----~
. :
~ ~ ~ ~ 1 ~ ~ . ' o ~ . . . . . . . . ~ . ~ . .
O ~ a~ ~ ~1 ~1 ~ ~ ~ c~ ~n o o o . ~, ~i op ~l ~
~1 C) ~ ~ ~ r~ I~ ~ c~ 1~ a~ oo ~1 ~ ~ . .
u~ cJ ~ . . . . . . . . . . . . .
a) o ~ a~n ~ o o o ,- :~
O ~ ~ ~ ~ ~ er ~ r ~ ~ ,:
~o~o :
Q~ . . , .
a~ In ~1 ~ ~ ~ ~
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C) n ~ o o ~ ~ ~n :~ ~ rJ ~ ~ ~ ~ ~ ~ ~ ~ ~
~ ~ :
. O ~ c~ o ~ ~ ~
~ p:; z ;~l ~
.
17, 217-F
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for drying water-wet methyl chloride which consists of distilling the water-wet methyl chloride in the presence of from 10 to 40 molar % hydrogen chloride based on the total weight of hydrogen chloride, water and methyl chloride, under superatmospheric pressure and a reflux ratio of from 1.3 to about 4, and a temperature of from 100°C to the azeotrope boiling point under the pressure of said distillation, thereby to produce a bottoms from said distillation, of not more than 36% aqueous hydrochloric acid and an overhead of methyl chloride and hydrogen chloride containing less than about 400 molar ppm water.
2. The method of Claim 1 wherein said molar quantity of HC1 is from 12-25%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA260,895A CA1069457A (en) | 1976-09-10 | 1976-09-10 | Process for drying water-wet methyl chloride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA260,895A CA1069457A (en) | 1976-09-10 | 1976-09-10 | Process for drying water-wet methyl chloride |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1069457A true CA1069457A (en) | 1980-01-08 |
Family
ID=4106823
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA260,895A Expired CA1069457A (en) | 1976-09-10 | 1976-09-10 | Process for drying water-wet methyl chloride |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1069457A (en) |
-
1976
- 1976-09-10 CA CA260,895A patent/CA1069457A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |